Dieholder for a press



Sept. 1, 1970 T. HEMINGWAY 3,526,122

DIEHOLDER FOR A PRESS Filed Sept. 11, 1967 2 Sheets-Sheet 1 Sept. 1, 1976 T. HEMINGWAY 3,525,122

DIEHOLDER FOR A PRESS I Filed Sept. 11, 1967 2 Sheets-Sheet 2 United States Patent US. Cl. 72-462 7 Claims ABSTRACT OF THE DISCLOSURE A press having clamping means by which a work tool can be clamped to the lower surface of the upper crosshead of the press. The clamping means includes a rod to which the tool is attached and to enable the press to be used for the process of upsetting in which no tool is clamped to the crosshead, the rod is retractable into the crosshead to provide an unobstructed lower surface on the crosshead.

This invention relates to presses and press tool clamping mechanisms.

Conventionally the upper press tool of a press is held to the upper crosshead by means of a rod mounted in the upper crosshead and extending below the lower surface thereof; the rod is connected to the tool, for example by a cotter, and spring means continuously urge the rod upwards and thus the tool against the crosshead.

In the process of upsetting, the upper tool is ideally provided by a plate which can balance on top of the workpiece and be acted on directly by the upper crosshead. However, with the tool clamping rod extending below the lower surface of the crosshead this means a lengthy manual job of removing the protruding rod or having it accommodated in a location hole in the top upsetting plate.

According to the present invention the tool clamping means for the upper crosshead of a press include a rod having a clamping position in which it extends below the lower surface of the crosshead to clamp a tool to the crosshead, and an inoperative position in which it does not extend below that surface, and means for retracting it into the crosshead.

Preferably the rod is located in an inner cylinder to move axially therewith and said inner cylinder serves as a piston in an outer cylinder mounted in the upper crosshead. Fluid means may be introduced under pressure between the inner and outer cylinders to urge the inner cylinder downwards to release a tool, or upwards to retract the protruding rod into the outer cylinder.

Spring means surrounding the rod bias the rod towards its inoperative position to provide the tool clamping force.

Preferably the rod is rotatably mounted in the inner cylinder and means are provided to rotate the rod relative to the inner cylinder through at least 90.

A work tool may be secured to the lower surface of the upper crosshead by a cotter engaging a surface on the tool and extending through an opening in the rod.

An embodiment of press crosshead and tool clamping means, in accordance with the invention, will now be described, by way of example only, with reference to the accompanying drawing in which FIG. 1 is a vertical view of a press crosshead, tool clamping mechanism and work tool, partly in section, and

FIG. 2 is a scrap view showing an alternative arrangement of work tool.

-In FIG. 1 of the drawings, the upper press crosshead is shown at 12, the tool clamping mechanism comprising an outer cylinder 13 mounted in the crosshead, an inner 3,526,122 Patented Sept. 1, 1970 cylinder 14 vertically slidable in the outer cylinder, a rod 15 mounted in bearings 16 for rotation in the inner cylinder but restrained against axial movement relative to the inner cylinder, the lower end 17 of the rod extending below the lower surface 18 of the upper crosshead in its tool clamping position illustrated. The rod is also guided in a bronze bush 20 at the lower end of the outer cylinder to guide it during rotation. The upper end of the rod carries an internally splined part 22 which engages with corresponding splines on the shaft of a rotary motor 23 which is rotatable through at least The rotary motor is hydraulically operated and is supported on a cover plate 14' bolted to the cylinder 14. A guide 40 secured to the outer cylinder 13 projects through an opening offset from the centre of the plate 14' to prevent rotation of the plate and the inner cylinder when the motor 23 is actuated. A plurality of disc springs 24 arranged in a stack are located around the central portion of rod 15 within the inner cylinder 14 and bear against a shoulder 25 on the rod which abuts against an inwardly projecting flange 26 on the inner cylinder and against a bush 29 bolted to the lower end of the outer cylinder; the disc springs serve to provide a continuous force urging the inner cylinder and rod upwards into the outer cylinder towards the inoperative position of the rod. The bore of the outer cylinder is enlarged at 27 adjacent its upper end and slidable in the enlarged portion is an annular outwardly extending flange 28 of the inner cylinder which acts as a piston ring; an inlet (not shown) to the enlarged bore portion 27 is provided for supply of pressurised fluid which acts on the flange 28 to force the inner cylinder and consequently the rod 15 downwards against the action of springs 24 when it is required to release a tool. A further inlet (not shown) to the portion 30 of the bore 27 below flange 28 is provided for pressurised fluid which acts on flange 28 to force the inner cylinder and the piston rod arrangement upwards to clear upper crosshead lower surface to enable a top upsetting tool to be used.

A work tool 31 with a nimonic facing is detachably secured to the lower surface of the crosshead 12. The lower end 1'7 of the rod 15 projects into a recess 32 in the work tool and a cotter 33 extends through an opening 34 in the lower end of the rod and engages a surface 35 on the tool.

The arrangement is shown in its normal tool clamping position; when a new tool is required, cotter 33 is removed, having first released the pressure therefrom by introducing fluid under pressure above the flange 28 on the inner cylinder. The tool is removed and a replacement fitted, prior to re-fitting the cotter and removing the fluid pressure from above the flange. The disc springs 24 apply the clamping force to the new tool. The tool can be rotated through at least 90 relative to the crosshead by releasing the pressure between the tool and the crosshead and then energising motor 23 to rotate the rod with the tool still attached thereto. When it is required to use the press for upsetting, fluid under pressure is introduced above flange 28 to enable the cotter to be withdrawn and the tool removed from the crosshead and fluid under pressure is then applied below the flange 28 to lift the inner cylinder 14 with disc springs 24 and rod 15 relative to the outer cylinder sufliciently for the rod to be retracted into the cylinder into its inoperative position, thus leaving the lower surface 18 of the upper crosshead free to engage the upsetting tool.

In the alternative arrangement illustrated in FIG. 2, the Work tool comprises two parts 36 and 37, with part 36 serving as an extension to the rod 15. The part 36 is of cylindrical form having a central recess 38 into which the end 17 of the rod projects. A cotter 33 extends through the opening 34 in the rod and secures the extension part 36 to the rod. The part 37 of the work tool has a central recess into which the rod extension projects and the part 37 is secured to the rod extension by a further cotter 39 which extends through an opening in the extension and engages an adjacent surface on the part 37 of the tool. The two-part tool is removed from the rod by first releasing the clamping pressure to enable the cotter 33 to be withdrawn and then cotter 39 is removed to separate the two parts of the tool.

What is claimed is:

1. A press having a crosshead and means for clamping a tool to the lower surface of the crosshead, said means including a rod located in a first cylinder to move axially therewith, said first cylinder serving as a piston in a sec ond cylinder mounted in the crosshead, and means by which fluid is introduced between said piston and said second cylinder to displace the rod between an inoperative position in which it is within the crosshead and does not extend below the lower surface thereof and a clamping position in which a part of the rod extends below the lower surface of the crosshead in which position the rod is capable of clamping a tool to the crosshead.

2. A press as claimed in claim 1 in which spring means bias the rod towards its inoperative position to provide a tool clamping force.

3. A press as claimed in claim 1 in which said spring means comprise a stack of disc springs surrounding the rod with one end of the stack acting against an abutment on the rod and the other end of the stack acting against the lower end of the second cylinder.

4. A press having an upper crosshead and means for clamping a tool to the lower surface of the crosshead, said means including an outer cylinder mounted in a recess in the lower surface of said crosshead, an inner cylinder which serves as a piston in said outer cylinder, inlet means through which fluid under pressure is introduced into the said outer cylinder to displace the piston, a rod rotatably mounted in the inner cylinder and movable axially therewith, said rod having an inoperative position to which it is biased and in which it does not extend below said lower surface and a clamping position in which it extends below said lower surface and means for rotating said rod relative to the inner cylinder through at least 5. A press as claimed in claim 1 having means for rotating the rod relative to the first cylinder which comprises a hydraulically operable motor coupled to the rod and supported on the first cylinder.

6. A press as claimed in claim 5 in which said rod defines an opening adjacent its lower end, a tool fits onto the lower end of the rod and a cotter extends through said opening in the rod and engages a surface on said tool to clamp said tool to the lower surface of the crosshead.

7. A press as claimed in claim 5 in which said rod defines an opening adjacent its lower end, an extension member fits over the lower end of the rod, a cotter extends through said opening and engages a surface on said extension to clamp said extension to the rod, a tool fits over the lower end of said extension and a further cotter extends through an opening in the extension and engages a surface on the tool to secure said tool to the lower surface of said upper crosshead.

References Cited UNITED STATES PATENTS 2,984,176 5/1961 Somer 295 3,106,110 10/1963 Senn 72-462 3,111,895 11/1963 Kraft 100295 3,301,037 1/1967 Beard 72-481 FOREIGN PATENTS 713,071 10/ 1941 Germany.

F CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner US. Cl. X.R. 

